I have a 1995 Cherokee xj 4.0 Bone Stock 110k automatic It ran strong when i shut it off then 3 months later when i started it again, it fired right up but
beyond 20% throttle i get far less response then i should, it idles great and the problem is 100 times worse when cold but even when warm never seems to get more than 60- 70% of what it used to have. I have done the following, fuel pressure checked out good, has brand new plugs (tried 2 new kinds no difference) wires, distributor cap, rotor, throttle position sensor,MAP sensor, Idle air control valve, air filter, in line fuel filter, cleaned injectors and checked flowed freely new o rings on injectors. pulled out a plug and had excellent spark very bright
ran seafoam and other injector cleaner through no change, finally cut out cat
which helped a little but still has no guts in the middle, then put new O2 sensor in. it seems like if i let off the throttle i accelerate faster. Engine lacks the torque it used to have, but revs freely and doesnt seem to backfire. Transmission shifts firmly and in the correct positions, is not sticking in any gears. Wide open throttle only yeilds about 80mph tops and any little incline makes the truck strugle and downshift.

I hope i have been descriptive enough, im pulling my hair out, i dont want to surrender to a mechanic...

Thanks!

 

Bad fuel? restriction somewhere else in the exhaust?

 

Have run 2 tanks of fuel, and i cannot be sure about the muffler at this point, but muffler is in good condition and seems to flow freely engine winds right up to 5k without any noticeable hesitation?

 

also, when the engine is under full operating temp aka 2 minutes or less from startup, I can push the pedal to the floor and acceleration is so poor it feels like it loses ground vs holding the throttle at 20% the engine really cant be starving for air, so it must be starving for fuel or have poorly times spark right? Timing maybe?

 

I would fuel pressure/flow check next i think.....

 

How do you flow check? I have a suspicion that maybe the fuel pump isnt moving the volume it needs to, but when the volume demand is low it can achieve proper pressure, how likely is it to be the in tank screen?

 

I pulled the inspection cover off the tranny and found there is a crack in the
flywheel from the center extending about 3 inches outward i had already tightened all of the converter bolts with locktight which eliminated the ticking noise from them being loose, when running the flywheel looks like it is not spinning laser strait could this be throwing off the time via the
crank position sensor? how true do they normally spin the awkwardness of the spin causes the flywheel to get closer and farther away from the block, not like an elipse where the flywheel looks like it is going up and down vs the block.

dont want to put the time into changing that if it has no potential of being the culprit of my power loss, need the power back then fix the other stuff